The NIH sponsored "Mortality and Morbidity in Hemodialysis Patients: Full- Scale Trial" is a 7 year prospective randomized multicenter study designed to determine whether an increased delivered dose of hemodialysis and/or the use of high-flux/biocompatible dialyzer membranes, reduces mortality and morbidity in patients with end-stage renal disease (ESRD). Nine- hundred participants will be recruited by 15 clinical centers (60 patients/center) utilizing a 2 x 2 factorial design where patients will be randomized to receive: 1) a KT/V of 0.95 (range: 0.9-1.1) or 1.4 (range:1 .3-1.5); and 2) high-flux/biocompatible or low flux/bioincompatible dialysis membranes. Mortality due to all causes will be the primary endpoint. Secondary outcomes measures will include morbidity as assessed from non-vascular access related hospitalizations with particular emphasis on cardiovascular complications and severe infections, as well as the decline in serum album in as an index of nutritional status. The Emory Clinical Center proposes to recruit participants from 4 Atlanta dialysis units, three of which are affiliated with Emory University (REN Atlanta, REN Emory Il, DCI Crawford Long), and one community dialysis center (REN Piedmont). The combined census includes 328 in-center maintenance hemodialysis patients of which 258 (79%) are eligible according to the criteria outlined in the MMHD protocol (goal=108 patients/center). Due to our referral base and the ethnic mix of our community, 88% of our patients are black, 11% are caucasian, and the remaining 1% are hispanic or oriental; 46% are male and 54% are female. All dialysis units are equipped to provide high-flux hemodialysis, and 95% of the patients tolerate a dialyzer blood flow equal to or more than 400 ml/min. For the participating dialysis units, the mean KT/V was 1.26 (range: 0.73-2.07) and normalized protein catabolic rate (PCRN) was 0.91 (range: 0.32-2.19) for February 1994 (N= 328). The Principal Investigator, Co-investigator's, Study Coordinator, and Dietician/Data Collector, have previous experience with collaborative clinical trials, clinical studies in hemodialysis patients, and are competent in the management of ESRD patients. In previous clinical studies we have been successful in patient recruitment, achieving high levels of patient retention and compliance with visits, as well as quality control measures. Thus, we are confident that we have the required number of patients and expertise to successfully complete this clinical trial.